Speaking on Friday morning, the Deputy Prime Minister said the Greens are "people of integrity" and will be rocked by Metiria Turei's failed gamble.

"Literally a few short weeks ago they were at 15 percent, and now to be below five, for them will be a real shock," she told The AM Show.

If the Greens don't make it back into Parliament, Ms Bennett says it'll give National a chance to "own" the conversation on environmental issues.

"We're big on the environment and I don't think National often gets a word in there as much because the Greens used to sort of own that space a little bit. I'm Climate Change Minister and all that sort of stuff, so if it means owning the environment and the difference we're making in it and how supportive we are, then we might go for that."

National's environmental record over the past nine years has often come under criticism from both political opponents and environmental lobby groups.

The Greens hoped Ms Turei's revelations she lied to WINZ in the 1990s to get extra money would galvanise support on the left, but it appears to have backfired spectacularly. An initial jump in the polls was short-lived, after it became apparent Ms Turei had left out crucial details of her story, and evidence she was committing electoral fraud around the same time also surfaced.

The beneficiary of the Greens' slide in support has been Labour, up to 37 percent in Thursday's poll - a massive 14 points above where it was before Jacinda Ardern took the leadership.

"We're happy to take votes from anywhere. I see the Nats have gone down 3 percent, so we're also happy about that. We're focused on what Labour has to do to be in the best position possible to lead the Government."

Paula Bennett and Kelvin Davis on The AM Show.
Photo credit: The AM Show

"We are getting people saying they are switching from National to Labour. Five weeks to go, and we're feeling very confident."

Though New Zealand First's position as the third-biggest party in New Zealand seems to have been cemented, Mr Davis says the Greens will still be the first cab off the rank - if they get the numbers to make it back into Parliament.

"If the Greens are still there after the election, we'll pick up the phone and talk to the Greens first."

Ms Bennett says if the Greens do make it back in, it'll probably be at the expense of Labour.

"The left have kind of shifted around and swapped votes effectively... for all that's gone on in the last two weeks, for all that we've heard about this great big effect of Jacinda and everything else, you're talking 2 or 3 percent, and what you are talking is that left vote moving around."

But she knows fourth-term Governments in New Zealand are rare, and National is fighting against history.

"A fourth term? Any Government going for a fourth term is a big call to make, and the public were always going to look at it and that sort of thing."